Nodes in a packet communications network referred to as access nodes are more particularly responsible for routing packets sent to or received from user gateways over the final terminating connection between the communications network and the user. This connection is commonly referred to as the “last kilometer”. A digital subscriber line access multiplexer (DSLAM) can execute this access node function and manage one or more digital subscriber lines. Alternatively, the access node can be a wireless access node, for example. The user gateway constitutes the unique entry point to the devices of one or more users.
A stream is characterized by a number of characteristics common to a number of packets. These characteristics, also known as identification elements, can be present in various layers of the Open Systems Interconnection (OSI) model. They can correspond to the contents of the source and/or destination address fields (layer 3) or any other field in the header of the packets, in particular the protocol type (layer 3) and the port numbers of TCP or UDP segments (layer 4). In the uplink direction, i.e. for packets of a stream coming from a user gateway and going to the access node, the user gateway is responsible for determining a stream category related to quality-of-service requirements and then for applying a quality-of-service profile as a function of the category of the stream concerned. It might be a question, for example, of giving preference to data packets of real-time calls over packets of applications such as internet browsing.
Where the downlink direction is concerned, i.e. for packets sent by the access node to the user gateway, there are bandwidth management techniques enabling sharing of bandwidth resources as a function of a stream category related to quality-of-service requirements. One such technique is described in US patent application 2005/0005023, for example. A table of streams is used to control traffic going to a user. When a packet of a stream is received, attributes representing the category of that stream are extracted and various masks applied in order to obtain an access key to the table of streams. That access key is used to define the quality-of-service profile to be applied to transmit the packets of the stream. The rules for managing the table are defined statically by the access node operator. Moreover, in peer-to-peer networks, some attributes are assigned dynamically, for example the TCP port number. Since the table management rules are defined statically, it follows that the method is not able to adapt to the appearance of streams that relate to categories that have not yet been referenced, for example streams transmitted in the context of the peer-to-peer network or in the context of implementing new applications that are unknown to the access node operator but that are nevertheless made available to users of the network of that operator from outside the network.
There is therefore a need for a technique for defining and modifying rules for managing the quality of service for user traffic going to the gateway.